21.14 Performance Schema and Plugins

Removing a plugin with UNINSTALL
PLUGIN does not affect information already collected for
code in that plugin. Time spent executing the code while the
plugin was loaded was still spent even if the plugin is unloaded
later. The associated event information, including aggregate
information, remains readable in
performance_schema database tables. For
additional information about the effect of plugin installation and
removal, see
Section 21.5, “Performance Schema Status Monitoring”.

A plugin implementor who instruments plugin code should document
its instrumentation characteristics to enable those who load the
plugin to account for its requirements. For example, a third-party
storage engine should include in its documentation how much memory
the engine needs for mutex and other instruments.